The invention relates to open power boats of the type used in fishing tournaments and other recreational boating and particularly to the hull configuration thereof.
In those vee entry boats having top speeds in excess of 60 mph, with which the invention is particularly concerned, the choice of hull configuration has conventionally involved various trade offs among the more desirable criteria which include safety and fuel economy on the one hand and high speed performance on the other. These trade offs are no where more evident, in a conventional vee planing hull, than in a sharp course correction from "full out" on plane running where, from the standpoint of safety, it is necessary to come substantially off speed to achieve the increased wet planing area necessary for turn tracking stability. This, of course, produces a significant increase in drag with a concomitant decrease in fuel efficiency both in the turning maneuver and bringing the boat back to full plane after the course correction. It is the purpose of the invention to resolve these conventional trade offs as related to high speed course correction.
High speed turns are one of the more dangerous boating maneuvers and are particularly unforgiving of the novice boater who has not mastered the "feel" for coordinating trim and throttle adjustments at the inception, and execution, of the turn. Indeed, it is the rare expert who, even when throttling back from top speed and entering a proper trim adjustment, has not felt unanticipated stern slippage or "chine walk" and porpoising associated with such maneuvers that are wont to capsize the boat.
The prudent boater thus comes drastically off speed to execute a sharp turn. The decrease in speed, of course, results in a greater wetted area of the hull, puts more chines in the water and, most importantly, reduces the magnitude, or arc, of the lay over angle which the outer running surface of the hull on the inside of the turn makes with the water surface. The consequence of the latter is that with a lesser arc of downward movement in a given time frame the laying over of the outer running surface into wetting contact does not produce the violent slapping and bouncing from the surface that initiates repeated slapping impacts and violent stern slippage that is characteristic of a high speed turn under full throttle where the arc of descent is substantially greater from the full on plane position. Additionally, the greater wetted area in an off speed turn places more of the after running surface wedges in hard water producing a bow down attitude to reduce porpoisingin a turn.
The foregoing is the typical performance of conventional vee hulls having the usual planar running surfaces, separated by chines, on either side of the keel line running surface which lateral, planar running surfaces and the central keel line running surface, when viewed in transverse section adjacent the aft end of the boat, exhibit a typical V shape terminating, laterally, at outer chines continuous with the sides of the boat.
As related to the present invention, it is important to note that prior art hulls of the type herein contemplated have employed planar, outboard running surfaces to more easily "slip" the water and avoid low speed cavitation. Where after wedges have been employed in prior art hulls they have been confined to one or more of the running surfaces inboard of the outermost running surfaces. The disclosure in applicant's U.S. Pat. No. 4,233,920 is exemplary.
Atypical hull configurations such as shown in U.S. Pat. No. 3,216,389 where all the running surfaces are concave are distinguishable in kind from the high performance type hulls herein described since inherent hull cavitation over the entire speed range of such a boat is inconsistent with the purposes of the present invention which is directed to performance parameters in that speed range beyond the reach of such atypical hulls.